1. Field of the Invention
The present invention relates generally to a manual data input means for a computer or the like, and more particularly to a stylus and stylus sensing pad for data entry.
2. Description of the Related Art
Typically, computers include keyboards or keypads for manually inputting data to the computer. The computer user presses the keys of the keyboard sequentially to input the data. The keyboard keys, when depressed, transmit, for example, an interrupt signal to a keyboard controller which in turn polls the keyboard to ascertain which of the keys has been depressed. A scan code corresponding to the pressed key is then generated and forwarded to a queue for retrieval by the computer when a keyboard input is sought.
Keyboards and keypads occupy a considerable amount of space since a key must be provided for each letter of the alphabet as well as additional keys for special symbols, functions and the like. Today's computer keyboards often have over 100 keys. The arrangement of the keys is frequently the "QWERTY" arrangement (so called due to the keys aligned above the left hand) commonly used by typists and the spacing of the keys is generally required to correspond to finger spacing of the human hand for efficient data entry. The result in a rather large keyboard.
A large keyboard is usually not a problem with desk top computers or other stationary computer systems. However, portable computers are becoming smaller and smaller and in such small computers the size of the keyboard is frequently a limiting factor in the extent to which the size of the computer may be reduced. So called "smart" devices are also becoming more common, such devices including schedulers or organizers, phone directories, electronic dictionaries and spelling checkers, translators, and portable bar code scanners. Each of these devices commonly include a key pad for manual data input. Many small keyboards abandon the "QWERTY" arrangement in favor of an alphabetic arrangement of the keys; however, this also tends to slow data input and does not reduce the size of the keyboard in and of itself since no keys are eliminated. In some cases, small keypads can even be too small for use by someone with large fingers.
Recently, input pads for computers having smooth surfaces on which data is written by a stylus have been developed. While such pads eliminate the keys and the need for typing experience and also may be smaller in size than a full size keyboard, considerable difficulty has been encountered in interpreting the handwritten input by the user, be it printed or cursive. This is particularly true due to variations in handwriting of different individuals. Even the development of software to interpret cursive writing of individuals has been slow and unsatisfactory. Furthermore, handwritten input tends to be slow, the usual maximum speed for cursive writing being approximately 25 words per minute.